Before an American dentist killed the beloved lion known as Cecil outside a Zimbabwe national park, the animal "suffered incredible cruelty for at least 10 hours, severely wounded and slowly dying."

That's according to Andrew Loveridge, an Oxford biologist who studied Cecil for eight years and recounts new research on the lion's death in Lion Hearted: The Life and Death of Cecil and the Future of Africa’s Iconic Cats.

Loveridge analyzed GPS data from the lion's collar alongside statements from those involved in the July 2015 hunt for the memoir, an excerpt of which published in National Geographic.

"Clearly, although the wound was severe, the arrow had missed the vital organs or arteries that would have caused rapid blood loss and a relatively quick death," Loveridge writes.

Cecil survived between 10 and 12 hours after his initial wounding, according to the researcher's analysis of accounts and data:

"Certainly, the lion was so incapacitated that in all those hours he’d been able to move only 350 meters from the place where he was shot."

The killing shot came from a compound bow, Loveridge writes, perhaps after an earlier arrow failed to kill the lion over the course of hours.

If Walter Palmer, the American who killed Cecil, wanted to submit him to record books as a bow-hunted trophy, killing him sooner with a bullet would have been out of the question, the author notes.

Palmer, a Minnesota dentist, lured the 12-year-old lion outside the protected confines of Hwange National Park using an elephant caracas, Loveridge writes. The death of the black-maned lion on the guided hunt sparked outrage around the globe.

Zimbabwean authorities said Palmer paid at least $50,000 to hunt and kill the lion. And while he faced intense criticism for the act — Palmer closed his dental practice and went into hiding for a time — charges against him there were ultimately dropped.